Some example embodiments of inventive concepts relate to a non-volatile memory device and/or an operating method thereof.
In general, a memory device may be volatile or non-volatile. A volatile memory device may lose data stored therein at power-off. A non-volatile memory device may retain data stored therein at power-off. For example, the non-volatile memory device may be a read only memory (ROM), an electrically erasable programmable ROM (EEPROM), or the like.
A flash memory device, such as flash EEPROM, may be different from a conventional EEPROM in terms of its structure and operations. The flash memory device may perform an electric erase operation by the block unit and a program operation by the bit unit.
Threshold voltages of programmed memory cells in flash memory devices may vary due to various causes (e.g., floating gate coupling, charge loss with the lapse of time, etc.). A variation in threshold voltages of memory cells may affect the reliability of read data.